C MIL Building Renovation By CASTOR FIBER Architecture Studio

The C MIL Building Renovation by CASTOR FIBER architecture studio is a striking example of adaptive reuse, transforming a former military facility in Brussels into a modern, functional residence and office. Originally a brutalist concrete structure with steel windows, the building was located at the highest point of the green belt surrounding Brussels, offering panoramic views of the city nearly 20 kilometers away. Its strategic location and circular form became the foundation for a careful, context-sensitive renovation.

The client engaged architect Maarten Dekoninck early, emphasizing minimal intervention and a focus on clarity. The guiding principle, "to create is to delete", informed the design process. Superfluous elements were removed, while non-load-bearing interior walls offered flexibility for spatial reorganization. The exterior was upgraded with insulated plaster that respects the original raw concrete aesthetic, while windows maintain a sleek contemporary interior look complemented by steel finishes on the outside. Ecological shou sugi ban black wood under the windows integrates the building harmoniously with the surrounding nature reserve.

Brutalist character enhanced: Utilities were cleverly installed externally, leaving the concrete pillars and masonry intact. Patio-side walls were replaced with floor-to-ceiling glass, blurring boundaries between the interior and the lush landscape outside. The renovation preserves the building’s circular layout while introducing functional zones that encourage exploration, with hidden sliding doors maintaining a flexible, uninterrupted flow.

Inside, the home exudes tranquility and intimacy. Cement-based finishes soften the raw textures of concrete and red brick, while the heavy window profiles moderate light and add visual weight. On one level, over 300 m² of space embraces the central patio, creating a private, contemplative environment. The sequence of spaces guides residents naturally through light-filled rooms and vistas toward the surrounding greenery.

Sustainability and adaptive reuse are central to the project. By reimagining a military structure as a home and office, CASTOR FIBER demonstrates the potential of renovation, repurposing, and minimalistic design. The project celebrates Brutalist architecture while introducing a modern, human-centric experience, proving that even rigid, utilitarian buildings can be transformed into elegant, functional living spaces.

This renovation is not only a testament to the power of context-driven architecture but also a vision for the future of sustainable urban development, where reuse and thoughtful design extend the lifespan and relevance of existing structures.

All the photographs are works of  Laurent Brandajs